Glossary

For information purposes, we provide a glossary of terms used in relation to the forest environment (diseases, insects, trees):

Acari (Acarian)
Order included in the class Arachnida. The members of this order (mites and ticks) are very tiny organisms with an unsegmented abdomen and generally four pairs of unjointed legs.
Acorn
Hard fruit of the oak tree, which contains the seed.
Anthophagous
Feeding on flowers.
Anthophilous
Fond of flowers. Organism that has a close relationship with flowers, normally including the collection of pollen or nectar as a food source.
Anthracnose
Foliar disease characterized by reduced growth of some portions of the lobes and by the development of necrotic lesions between the veins and on the leaf margins; these lesions may spread to the entire leaf and then the buds and, in extreme cases, the twigs.
Antibiotic
Chemical substance capable of preventing the development of micro-organisms.
Antifungal
Capable of killing fungi or impeding their development.
Apex
Tip or top of an animal or plant structure.
Apothecium
Cup-shaped ascomatum found in certain ascomycetes fungi and containing the reproductive structures (asci and ascospores).
Apterous
Wingless.
Arthropoda
Phylum of invertebrate animals that possess an exoskeleton and a segmented body with jointed appendages (legs). Arthropods include crustaceans, spiders and insects.
Ascomatum
Sexual stage of ascomycetes fungi, either an apothecium, a perithecium or a cleistothecium, which contains the asci and ascospores.
Ascospore
Fungus spore produced within an ascus.
Ascus
Bag-like structure that develops within an ascomata (sexual stage of ascomycetes fungi) and is made up of a membrane in which ascospores are produced; the ascospores are discharged from the ascus at maturity.
Asymmetrical
Having corresponding parts that are irregularly arranged in relation to one another. Opposite of symmetrical.
Atrophied
Describes an organ or part of a body that is reduced in size, rudimentary.
Bark
The outer covering of trees.
Base of tree
Part of the tree consisting of the first 25 cm of trunk.
Basidiospore
Fungus spore produced on a basidium.
Blade
Thin, flat part of a leaf.
Blight
Rapid browning or blackening of leaves, which subsequently die, caused by the deterioration of growing tissues.
Blister
Circular bulge caused by the excessive growth of cells in part of a leaf, often with fungal cells mixed in.
Borer
Relates to an organism that bores into and feeds on the woody and non-woody portions of plants.
Brachypterous
Having reduced wings that are shorter than the abdomen.
Branch
Secondary woody stem arising from the trunk of a tree and bearing shoots.
Bud
Plant organ containing the immature tissues that will become a leaf, branch or flower.
Bulb
Swelling at the stem base in fungi.
Callus
Thickening and hardening of the cambium tissues which occur as part of a plant's response to a wound.
Cambium
Fast-growing tissue that produces wood and phloem (vascular cambium) and bark (cork cambium).
Canker
Lesion of the cambium and the living bark of trees that alters and kills these tissues in a localized area.
Carpophore
Structure bearing the spores of a fungus, often composed of a cap and a stem.
Casebearer
Any of numerous insects that hide under a case, a shelter made by cutting and tying pieces of leaf together with silk; they feed and move around within this shelter. Casebearers are members of the order Lepidoptera .
Caterpillar
Larval form of the immature stage of Lepidopterans. Transforms into a butterfly or moth.
Catkin
A drooping cluster of flowers or fruits on a flexible axis (resembling the tassels on wheat).
Cell
(Entomology) A space in an insect wing partly or completely surrounded by veins.

(Cytology) The structural and functional unit of most living organisms.
Cellulose
A polymer of glucose molecules, used by plants as a structural supporting material. Paper is made up of cellulose.
Cephalothorax
Anterior part of the body consisting of the fused head and thoracic segments.
Cercus
One of a pair of appendages located at the posterior end of the abdomen.
Chelicera
The anterior, usually fanglike, pair of appendages in arachnids that are used to chew prey.
Chewing
Refers to the modified mouth parts of some insects that comprise a pair of mandibles enabling them to chew and tear up food.
Chewing-sucking
Refers to the modified mouth parts of some insects enabling them to chew and suck on food.
Chitin
Compound secreted by the epidermis in arthropods and making up the bulk of their cuticle (outer layer of the body).
Chrysalis
The pupa of butterfly. Intermediate stage between the larval stage and the adult in lepidopterans.
Class
Taxonomic level between Phyllum and Order. Eg, class Insecta
Claviform
Club-shaped.
Cleistothecium
Spherical ascomatum (with no opening) found in certain ascomycetes fungi and containing the reproductive structures (asci and ascospores).
Cluster
Group of flowers or fruits borne on a common axis.
Cocoon
Case of silk in which the pupa is formed.
Compound leaf
A leaf with two or more leaflets attached to a single leaf stem.
Cone
Reproductive structure of conifers consisting of a central axis covered with scales that are tightly pressed together. At maturity, it contains the seeds.
Cone-feeding
Feeding exclusively on the seeds and cones of conifers.
Conidiophore
Specialized hypha upon which one or more conidia are borne.
Conidium
Thin-walled spore produced asexually by certain fungi.
Conifer
Member of a group of trees commonly called softwoods or gymnosperms. The word gymnosperm, from the Greek gymnos (naked) and sperma (seed), means "naked-seeded." This refers to the fact that conifer seeds are not contained in fruit tissue. The seeds are instead borne on scales, which are grouped together to form cones. Most conifers have persistent foliage consisting of needles or scales.
Continuous boreal forest
Main subarea of the vast boreal zone, which is characterized by relatively dense stands containing primarily boreal coniferous species and shade-intolerant deciduous trees.
Coxa
The basal leg segment attached to the thorax and the trochanter bearing the femur.
Crepuscular
Pertaining to organisms that are active during the dim light of dusk or dawn.
Crown
The upper part of a tree.
Cultivar
A variety of plant cultivated on account of its favourable characteristics for horticulture, forestry or agriculture.
Cuticle
(Bionaty) Surface tissue layer of the cap of fungi.

(Entomology) Layer of material covering the body of arthropods. This covering is made hard and rigid by the chitin secreted by the epidermis.
Decay
Decomposition of wood caused by micro-organisms, mostly fungi. The wood generally becomes soft and crumbly, loses density and changes colour.
Deciduous forest
Subarea of the northern temperate zone, which is characterized mainly by sugar maple-dominated deciduous forests. This is the subarea with the greatest floristic richness.
Deciduous tree
Member of a group of trees commonly called hardwoods or angiosperms. The latter term comes from the Greek "angion (vessel) + "sperma" (seed), denoting the fact that the seed is carried in a fruit. Deciduous trees shed their leaves in autumn.
Decurrent
Refers to gills, folds, tubes or teeth that run down the stem of fungi.
Deeply notched leaf
Leaf that has deep sinuses cut into its outer edge.
Defoliation
Loss of all or some foliage caused by a chemical treatment or a pest organism.
Defoliator
Organism that feeds on the foliage of plants. Eg, insects that feed on and destroy whole leaves or parts of leaves.
Desiccation
Process of becoming dried out.
Detritivorous
Feeding on detritus, decomposing organic matter.
Diapause
A period of greatly decreased metabolic activity occurring in arthropods. This period may occur during any of various developmental stages depending on the species.
Discoloration
Change in the normal colour of wood following infection by a micro-organism.
Disease
Alteration of the normal functions of a whole plant or part of it, caused by a living or dead agent. The main agents involved in the initiation of disease are pollution, animals, fungi and other plants.
Diurnal
Pertaining to organisms that are active during the day.
Drupe
Fleshy fruit with a central hard core.
Ecological niche
Total way of life or role of a species in an ecosystem.
Ectoparasite
External parasite that lives permanently on the body of a vertebrate or in accessible openings, such as the nose or ears. They are obligate parasites during part of or their entire life cycle. This type of parasite lives on the outside of its host's body without entering it. Organism that lives off another organism without killing it.
Elbowed
Elbow-shaped.
Elongated leaf
Leaf that is a lot longer than it is wide.
Elytron
A scleotized fore wing that covers the hind wing like a sheath. Found in Coleoptera.
Endoparasitoid
Organism that lives inside and feeds on a single host, which dies after the parasitoid has completed its larval development.
Entomology
Part of zoology concerned with the study of insects.
Epidermis
Tissue covering the aerial portions of a plant.
Female flower
Part of the plant bearing the female sexual organ (pistil).
Filiform (threadliked)
Thread-like. Eg, a thin antenna whose diameter is the same or nearly from tip to base.
Floricolous
Pertaining to an organism that is associated with flowers. Frequenting flowers without harming them (eg, butterflies).
Flower
The reproductive structure of a tree or other plant consisting of the male and/or female parts.
Foliage
All the leaves of a tree.
Forest
Ecosystem that generally covers a large area and is composed of woody vegetation dominated by trees growing in a relatively dense pattern.
Forest tree species
Group of individuals that possess common characteristics and are capable of producing fertile progeny
Forested tundra
Subarea of the vast boreal zone characterized by a mosaic of stands of variable density and by tundra consisting mainly of shrubs and lichens. This plant formation is located at the tree line, and marks the division between the boreal zone and the arctic zone.
Form
General shape of a tree.
Four-sided
Geometric shape with four sides.
Free-living defoliator
Organism that feeds on and moves about freely on foliage. Eg, forest tent caterpillar
Frugivorous
Feeding on fruit or the reproductive structures of plants.
Fruit
Reproductive organ of plants that results from fertilization of the flower and contains the seeds.
Fungicide
Substance used to kill fungi.
Fungivorous
Feeding on fungi.
Fusiform (spindle-shaped)
Spindle-shaped.
Gall-forming
Relates to an organism that induces the formation of galls and feeds on their tissues.
Gall-inhabiting
Pertaining to an organism that lives in a gall made by a different insect.
Geophilous
Living in or on the ground.
Gill
Plate-shaped membrane located under the cap of a fungus; all of the gills together form the hymenium.
Girdling
Destruction of tissue (water conducting system) in a ring around a tree.
Glabrous
Lacking hairs or down.
Granivorous
Feeding on seeds.
Gymnosperm
See conifer
Haltere
Small knobbed structure representing the hind wings in dipterans.
Hamuli
Series of small hooks found in some insects that anchor the hind wings to the fore wings during flight.
Hematophagous
Feeding on blood.
Hemimetabolism
Incomplete metamorphosis in which there is no pupal stage. The larvae, also called nymphs, are inactive and resemble the adults.
Heteroconophagous
Feeding occasionally on seeds and cones, but usually lives and feeds on stems and needles.
Hibernaculum
A place or material in which young insect larvae hide during the winter.
Hibernation
Sleeplike stage in which an organism's metabolism is reduced to its lowest level.
Holometabolism
Complete metamorphosis in which a pupal stage occurs between the larval stage and the adult form. The pupa is inactive and looks very different from the adult.
Host
Organism harbouring a parasite.
Humicolous
Living in or on humus or leaf litter.
Hybrid
Plant obtained by crossing two genetically dissimilar parent plants.
Hyperparasite
Parasitic organism that lives off of another parasite.
Hyperparasitoid
Organism that attacks and lives on another parasitoid.
Hypha
One of many filaments that make up the mycelium or body of a fungus.
Hypovirulence
Reduced virulence in a micro-organism caused by genetic mutation or the presence of a virus.
Imago
The adult sexually mature stage in the life cycle of an insect after metamorphosis.
Insect
Invertebrate animal that has six legs.
Juices
Organic liquid contained in certain plant and animal structures, eg, plant sap.
Larva
Immature stage (between the egg and the pupa) in insects that undergo complete metamorphosis before becoming adults.
Larvarium
Tube or sheath made by a larva as its shelter.
Leaching
Process in which soluble substances in the soil are removed by the movement of water.
Leaf
Organ in plants that has various forms (needles, scales, etc.) and that carries on photosynthesis, producing energy for life.
Leaf-fall
Normal shedding of leaves in the fall.
Leaffolder
Insect that folds a leaf in two to make a shelter for hiding or feeding.
Leafroller
Organism that hides and feeds inside a leaf or the tip of a leaf that it has rolled-up into a cigar-shaped tube.
Leaftier
Organism that ties two or more leaves together with silk threads, forming a tube in which to hide and feed.
Lignicolous
Growing in or on wood.
Lignin
Main component of wood.
Litter
Uppermost layer of organic debris on a forest floor.

Lobe
Large division of a leaf.
Lower Arctic
Subarea of the arctic zone characterized by the absence of trees, continuous permafrost and tundra vegetation consisting of shrubs, herbaceous plants (mainly grasses), mosses and lichens.
Lumber
Wood processed in a sawmill.
Maggot
Whitish larva that resembles a worm and has no legs (example : fly larva).
Male flower
Part of the plant bearing the male sexual organ (stamen).
Mammal
Four-legged vertebrate of the class Mammalia, characterized by females that produce milk with which to feed their young.
Metamorphosis
All of the changes that an insect undergoes from the egg stage to adult form.
Mine
Gallery excavated by a larva in plant tissues, such as a leaf or bark.
Miner
Organism that feeds inside the blade of a leaf, between the epidermal layers, or beneath the bark of plants, by first excavating a mine into these tissues.
Mite
Acarian that feeds on plant or animal matter.
Mixed forest
Subarea of the northern temperate zone, which is dominated by mixed forests encompassing both coniferous boreal species and more southerly deciduous species.
Monophagous
Organism that feeds on a single host, whether plant or animal.
Morphology
Form and structure of living organisms.
Moult
Process whereby arthropods shed their old cuticle (external covering) and replace it with a new one.
Mushroom
Visible reproductive part of any of various fungi.
Mycelium
Vegetative part of a fungus, which is composed of a mass of hyphae and distinct from the fruiting body.
Mycetophagous
Feeding on fungi
Mycophagous
Feeding on fungi.
Native (indigenous)
A species that occurs naturally in an area.
Necrophagous
Feeding on dead or decomposing animal matter.
Necrosis
Alteration of tissues caused by the death of cells.
Nectar
Sweet liquid produced by special glands in flowers (called nectaries) to attract insects.
Nectarivorous
Feeding on nectar.
Needle
Long, narrow reduced leaf found in conifers.
Needle cast
Reddening or browning of needles, sometimes leading to premature shedding of foliage.
Needle-feeding
Living in and feeding on needles.
Needles borne in clusters (or bundles)
Group of needles joined together at the base
Nesting
Relates to an organism that spins a silk nest or tent in order to hide or feed.
Nodule
Globulose or elongated mass formed by certain fungi or a mixture of plant and fungal tissues.
Nutlet
Fruit, small nut.
Nymph
Synonym of the pupa or chrysalis stage found in insects with complete metamorphosis. The nymph is the final instar before the adult form. Nymphs are inactive and do not feed. Synonym of the larva in insects that go through incomplete metamorphosis. The nymph changes directly into the adult without going through a pupal stage; the nymph feeds and moves around. The term nymph is also used to describe the immature stages of acarians.
Nymphal
Pertaining to the nymph of arthropods (insects and arachnids).
Order
Taxonomic level between Class and Family. In insects, for example, classification in orders is based primarily on wing shape.
Organ
Group of tissues organized to perform a distinct function.
Ovoid
Egg shaped.
Parasite
Organism that lives on or in and feeds on a living plant or animal (host). The parasite gradually weakens the host and may or may not kill it.
Parasitoid
Insect larva that kills its host by consuming completely its tissues before pupation or metamorphosis into an adult.
Parthenogenesis
Form of reproduction in which an organism develops from an unfertilized egg.
Pathogen
Living or dead agent that alters the normal functions of a whole plant or part of a plant.
Pathogenic
Disease-causing
Pathology
Study of diseases and the effects they have on plants.
Perithecium
Flask-shaped ascomatum found in certain ascomycetes fungi and containing the reproductive structures (ascus and ascospores).
Persistent foliage
Characteristic of evergreen trees, that is, trees that do not shed their leaves in the fall.
Pest
Organism that causes serious damage to plants or foodstuffs.
Pheromone
Chemical substance emitted by an organism into the environment as a specific signal to another organism of the same species.
Phyllophagous
Feeding on the leaves of plants.
Phyllum
Taxonomic level between Kingdom and Class. Eg, phyllum Arthropoda composed of organisms with a segmented body. The body wall is more or less hardened and forms an exoskeleton.
Phytophagous
Refers to organisms that feed on plants.
Piercing-sucking
Organism that has mouth parts modified for sucking liquids from a host plant or animal. Relates to an organism that has specialized mouthparts for sucking the fluids from plants, thereby causing deformities or killing the affected plant sections.
Pit
One of many cavities or depressions on the fruiting body of morels.
Plurinucleate
Containing several nuclei.
Pocket of infection
Area in a stand or plantation where a disease originated.
Pollarding
Cutting back the crown of a tree (removal of dead, diseased or unwanted branches).
Pollination
Transfer of pollen from the anther of a flower to the stigma of a flower of the same species, resulting in fertilization.
Pollinivorous
Feeding on pollen.
Polyphagous
Feeding on several plant or animal species. Organism that develops on more than one host, eg, the gypsy moth, a polyphagous caterpillar feeds on both deciduous and coniferous trees.
Predator
Organism that hunts, captures and kills several types of prey (insects and acarians) over the course of its development.
Prepupa
Larval stage before pupation during which the insect stops eating and prepares for the pupal stage by making a cocoon, a shelter or attaching itself to an object with silk threads.
Proboscis
Tube-shaped mouthpart used by insects to suck nectar from flowers or suck other liquid food.
Pruning
Removal of branches from a tree, particularly beneath the crown.
Pupal
Pertaining to the stage between the larval stage and the adult in insects.
Pupation
Process whereby a larva tranforms into a pupa and later emerges as a mature insect.
Pycnidium
Spherical or flask-shaped structure (resembles a perithecium, but is asexual) within which conidia are formed.
Radicicolous
Living on or in roots. A parasite of roots.
Resilience
Ability of a biological organism to return to its original state following exposure to a biological, climatic or other stressor (example : pollution or other anthropogenic disturbance).
Resin blister
Swelling containing resin, a sticky gum-like substance.
Resinous
1. See resin blister 2. See conifer
Ring
Ring structure around the base of some fungi.
Root
Part of the tree that anchors it and absorbs nutrients from the soil.
Root collar
Transition point between the roots and the trunk.
Root rot
Decomposition of the woody tissue in roots causing the death of the cambium or bark of the roots, thus girdling the trees at the root collar and causing their death.
Root-feeding
Feeding on the roots of plants.
Rostrum
Rigid or segmented projection on the anterior part of the insect head bearing the mouth parts.
Round leaf
Leaf of variable shape whose length is nearly the same as its width.
Rust
Disease caused by a fungus that is parasitic on higher plants and may go through five different developmental stages, usually involving hosts. Following infection, orange pustules appear, possibly followed by premature shedding of foliage, witches' brooms or cankers.
Samara
A winged, one-seeded fruit.
Sap-feeding
Feeding on plant sap.
Saprophagous
Refers to organisms that feed on decaying or decayed plant or animal matter.
Saproxylophagous
Refers to an organism that develops in partially decomposed woody debris.
Saproxylophilous
Living on rotting wood.
Sawfly
Insect in the order Hymenoptera; the female has a sawlike structure that it uses for egg-laying.
Scale
(Botany) One of the small overlapping plate-like parts that make up the modified leaf of cedars.

(Entomology) Tiny, overlapping plates covering the wings of butterflies.
Scatophagous
Feeding on dung or excrement.
Scatophilous
Living in association with dung or excrement.
Sclerotin
Cuticular protein that has been hardened and darkened.
Sclerotized
Part of integument hardened through the excretion of calcium (crustaceans) or the deposition of sclerotin.
Seed
Fertilized ovule that contains an embryo and has the capacity to produce a new individual.
Seed-feeding
Feeding on seeds.
Seedling
Young plant that has grown from a seed.
Seminivorous
Feeding on grain or seeds.
Sexual reproduction
Reproduction that involves the fusion of genetic material from two distinct entities.
Silviculture
Practices aimed at ensuring wise harvesting of forest resources : conservation, regeneration, reforestation, cutting, etc.
Skeletonizer
Organism that devours the upper layer of leaves but not the veins.
Smog
Mixture of polluting particles and water drops in the atmosphere that forms a thick fog in industrial regions.
Snail-feeding
Pertaining to an organism that feeds on snails.
Species
Group of individuals that possess common characteristics and are capable of producing fertile progeny
Spore
Cell or group of cells capable of producing a new organism.
Spore print
Deposit of spores released into the air or onto a surface when a fungus cap is placed gills downwards.
Spot
Circular or nearly circular lesions that appear on a leaf blade. They have a central zone of necrotic (dead, brown) tissue colonized by a pathogen; this zone is surrounded by healthy, coloured tissue.
Stage
Distinct period separating the successive moults that occur during larval development. Period or phase in the life cycle of anthropods. Eg, egg stage, larval stage, pupal stage and adult stage.
Stoma
Microscopic opening, many of which are found on the underside of plant leaves, permitting transpiration and gaseous exchanges (pl. stomata).
Stump
Part of trunk with roots remaining after a tree has been cut down.
Stunted
Characteristic of a plant that has not developed normally and resembles a bonsai.
Stylet
Sharp, stiff structure in the mouth parts of certain piercing-sucking insects and barb in bees and wasps.
Sucking
Pertains to an organism that has mouth parts modified for sucking food, by means of a tube or proboscis (beak).
Sucking (lapping)
Pertains to an organism that has mouth parts designed for collecting flower nectar.
Taiga
Subarea of the extensive boreal zone characterized by open coniferous forest with lichens.
Taxonomy
Set of rules governing the classification and naming of species.
Terricolous
Living in the soil or litter.
Thallus
Vegetative plant body that is not differentiated into root, stem and leaves, although some analogous structures may be present.
Thrips
Any of numerous insects in the order Thysanoptera that are of minute size, have fringed wings (if winged) and feed mostly on plant juices.
Tick
Parasitic acarian that feeds on animal blood.
Trunk
Part of the tree that is generally straight and vertical, located between the root collar and the branches (crown).
Tubes
Cylindrical structures beneath the fungus cap constituting the hymenium in certain fungi.
Tubicolous
Dwelling in a tube, eg pine tube moth.
Tubular
Tube-shaped.
Twig
The smallest division of a branch which bears the annual shoot.
Univoltine
Having only one generation per season.
Variety
Subdivision of species, a group of individuals that have common characteristics (example : The different varieties of apples).
Venation
Distribution of veins on the wings of an insect.
Vesicle
Small, bladder-like structure.
Vestigial
Organ that is diminished in size and often nonfunctional.
Virulence
Measure of a pathogen's ability to multiply in a living organism and harm it.
Viviparous
Bringing forth living, fully formed individuals that are capable of feeding.
Volva
Cup-like sheath surrounding the stem base in some fungi, eg, Amanita; it is a remnant of the universal veil.
Webworm
Organism that spins a silk shelter in which to hide or feed.
Wilt
Drying out, loss of colour and shape of leaves, then twigs and branches, caused by a lack of water or the presence of toxins.
Windfall
A tree or trees thrown down by the wind or as a result of disease or senescence.
Witches' broom
Excessive proliferation of twigs from one location on a branch or several locations close together. The twigs in a broom are erect and compacted.
Woody debris
Dead and decomposing wood of various sizes.
Woody tissue
Plant tissue containing lignin, the main component of wood.
Worm-like
Resembling a worm.
Xylophagous
Feeding on woody tissues (wood).
Xylophilous
Growing in or living on wood.
Zoophagous
Refers to organisms that feed on animals (including other arthropods).

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